>>2230396This is how you tell. It's Perspective, not Photoshop.
All the horizontals (red lines) should converge at a common point.
That's the elevation of the camera (viewpoint) and the horizon (green line) runs through that.
I've re-sized windows so the top and bottom red lines are approximately correct, but the intermediate ones are still off.
This is 2-point perspective.
All the verticals (yellow lines) should also converge at a point.
I could extend the "paper" so you could see how they don't, but then the 'useful' part of the drawing would be too small to see.
You can do it yourself.
